Ozonizer

ABSTRACT

An ozonizer has a flat plate-shaped low voltage electrode  7,  a flat plate-shaped high voltage electrode  3  facing a main surface of the low voltage electrode  7.  The ozonizer also has a flat plate-shaped dielectric  5  and a spacer for forming a discharge gap  6  of a thin thickness in a laminating direction provided between the low voltage electrode  7  and the electrode  3,  an electrode cooling sheet  1  provided facing a main surface of the electrode  3  at a side opposite the discharge gap  6  for cooling the electrode  3.  The ozonizer also has a thermal conducting/electric insulating sheet  2  sandwiched between the electrode  3  and the electrode cooling sheet  1.  An alternating voltage is applied between the low voltage electrode  7  and the electrode  3  and a discharge is produced in the discharge gap  6  injected with oxygen gas to produce ozone gas.

This application is a reissue of application Ser. No. 10/155,068, filedMay 28, 2002, now U.S. Pat. No. 6,866,829 B2.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flat plate laminate ozone generatingapparatus including a plurality of laminated plate-shaped high voltageelectrodes and low voltage electrodes between which an alternatingvoltage is applied to produce a discharge and generate ozone gas, and inparticular, to an ozonizer which is an essential portion of the flatplate laminate ozone generating apparatus and which includes the highvoltage electrodes and low voltage electrodes and to which oxygen issupplied to generate ozone gas.

2. Description of the Related Art

FIG. 27 is a cross sectional drawing of a conventional ozonizerdescribed in, for example, Japanese Patent Publication No. 3113885“Discharge Cell for Ozone Generator”. In a conventional ozonizer, asshown in FIG. 27, a plurality of low voltage electrodes 7 composed ofapproximately flat plate-shaped rigid bodies sandwich a pair of block(s)25 on both sides and are superposed in a thickness direction of theplates to construct a number of electrode module laminated bodies. Theelectrode module laminated bodies are secured between an electrodepresser plate 22 and a base 24 by means of a plurality of fasteningbolts 21 passing through both side portions thereof in the laminatingdirection.

Each electrode module comprises a pair of upper and lower low voltageelectrodes 7, a pair of bilateral blocks 25 sandwiched between the lowvoltage electrodes 7, 7, dielectric unit(s) 30 disposed between the lowvoltage electrodes 7, 7 and situated at an inner side of the blocks 25,25 and a plurality of elastic spacers 26 for forming a plurality ofdischarge gaps provided for forming discharge gap(s) 6 at both sides ofthe dielectric unit(s) 30. The elastic spacers 26 constitute rod-shapesof a circular cross-section extending in a direction orthogonal to thepage.

The pair of bilateral blocks 25 is a rigid body of a conductive platematerial such as stainless steel plate(s), and, by intervening theblocks between both side portions of the low voltage electrodes 7, aspace of an equal gap amount is formed in the thickness direction of theblock(s).

Also, (all of) the drawings are expanded in the vertical direction andan actual thickness is made extremely thin, for example, 3 mm or less inthe case of the low voltage electrode 7 and 3 mm or less in the case ofthe block 25.

Cooling water passages 9 are formed inside the pair of upper and lowerlow voltage electrodes 7 and combine as a heat sink. Moreover, a coolingwater passage 9 is also formed in blocks 25 of one side. The coolingwater passages 9 inside the low voltage electrodes 7 are communicatedwith a cooling water inlet/outlet 12 provided in the base 24 via theblocks 25 in order to circulate cooling water as a coolant.

On the other hand, an ozone gas passage 8 is formed in a main surface ofthe low voltage electrode 7 facing the discharge gap 6 by means of, forexample, etching and the like. The ozone gas passage 8 is communicatedwith an ozone gas outlet 11 provided in the base 24 via an ozone gaspassage 8 formed in the blocks 25. Also, an oxygen gas inlet 10 forsupplying oxygen gas to the discharge gaps 6 along a directionorthogonal to the page surface is provided at both side portions ofdischarge gaps 6.

The dielectric unit(s) 30 disposed in the space surrounded by the upperand low voltage electrodes 7 and the bilateral blocks 25 is a thin sheetshaped rigid body comprising a sandwiched structure of a high voltageelectrode 3 sandwiched between a pair of upper and lower glass plates 5.The high voltage electrode 3 is a conductive thin sheet such as astainless steel sheet and the like and a portion thereof is led outsideas a feed terminal (not shown).

The discharge gap forming elastic spacers 26 provided for forming thedischarge gap 6 at both sides of the dielectric unit 30 are thin resinwire rods of a circular cross-section having ozone resistance propertiesand resiliency, and are disposed in the discharge gaps at apredetermined interval. A thickness of each elastic spacer 26 (outsidediameter) is set to be 5-6% larger than each gap amount of the dischargegaps 6 in a non-compressed state.

With such a setting, the elastic spacer 26 is compressed from above andbelow by the low voltage electrode 7 and the dielectric unit 30, and thedielectric unit 30 is resiliently pressed from above and below by anequal pressure by this compression and maintained in a central portion,in the vertical direction, of the above mentioned space. Consequently,the discharge gaps 6 of an equal gap amount are formed at both sides ofthe dielectric unit 30.

Moreover, in a case where rigid spacers are used instead of the elasticspacers 26, when the blocks 25 are fastened, of course, the rightspacers used are of a smaller diameter than the elected discharge gaplength (the height of the discharge gap in the laminating direction).Thus, the spacers are not compressed in the laminating direction in thedischarge gaps.

Next, operation will be explained.

When an alternating high voltage is applied between the low voltageelectrode 7 and the high voltage electrode 3, a dielectric barrierdischarge is generated in the discharge gap 6 via a dielectric 5. Oxygengas is dissociated to single oxygen atoms by this discharge, and, atroughly the same time, a three body collision is induced between theseoxygen atoms, other oxygen molecules and a wall and the like and ozonegas is generated. By using this mechanism and continuously supplyingoxygen gas to the discharge gaps 6, the ozone gas generated by thedischarge may be continuously derived as ozonized gas from the ozone gasoutlet 11.

An ozone generating efficiency derived from this discharge is normally,at most, 20%. That is to say, 80% of the discharge power heats theelectrodes and is lost. Also, the generating efficiency of the ozone gasis dependent on the temperature of the electrode (strictly speaking, thetemperature of the discharge gas), and the lower the temperature of theelectrode the higher the generating efficiency. Hence, the electrodesare directly cooled with cooling water and the like or a rise in gastemperature in the discharge gaps 6 may be suppressed by shortening thegap length of the discharge gap 6, and the ozone generating efficiencyis increased by increasing the electron temperature, ozone decompositionis inhibited and, as a result, an efficient ozonizer capable of derivinghighly concentrated ozone gas may be provided.

In a conventional ozonizer of such a construction, electrode cooling isone sided cooling of the low voltage electrode 7 side and the highvoltage electrode 3 is not cooled. Thus, in a case where the same(amount of) power is supplied, the temperature of the gas in thedischarge gaps 6 is about four (4) times that of a both side method forcooling the high and low voltage electrodes. Since the amount ofgenerated ozone which is decomposed is increased by this rise in gastemperature, the discharge power density input to the electrode must befurther increased and the ozone gas cannot be efficiently generated.

Moreover, when using the elastic spacers 26, because there are electronshaving sufficiently high energy in the discharge gaps 6 due to thedischarge, the elastic spacers 26 which are formed of an organicmaterial collide with the high energy electrons (discharge energy) bycontact with this discharge and the chemical bond incurs separationdamage. When the ozonizer is used in continuous operation, the elasticspacers 26 deteriorate in a short period of time compared to metalspacers and an even flow of gas is made impossible by thisdeterioration, and there are drawbacks in that efficiency is rapidlyreduced and the service life of the apparatus is shortened.

Also, even in a case where elastic spacers made of an ozone resistantTeflon (registered trademark) are used, the above mentioned high energyelectrons (discharge energy) collide and the chemical bond suffersseparation damage. Further, even if a material which is generally “flameretardant material” in air is used, as in the case of highlyconcentrated ozone or oxygen gas atmosphere “combustible material”,there is a problem in that a sublimation reaction of the elastic spacersis activated by the discharge energy at a portion disposed to directlycontact the discharge gap and clean ozone cannot be obtained.

On the other hand, in the case where the rigid spacers are used insteadof the elastic spacers 26, they are, naturally, designed to be of asmaller diameter than the elected discharge gap length when beingfastened via the blocks 25. Hence, when the discharge gaps 6 are tinygaps and a high concentration of ozone is to be generated, a pressureloss of the gap partitioned by the spacers 26 for forming the dischargegaps (pressure loss of the tiny gaps between the dielectric 5 and thespacers 26 for forming the discharge gaps) is much smaller than thepressure loss of the discharge gas passages (pressure loss of the gaspassages orthogonal to the page surface of FIG. 27). Thus, the even flowof gas is made difficult by the spacers 26 for forming the dischargegaps. Consequently, there are problems in that the ozone generatingefficiency is degraded and the ozonizer cannot be made compact.

Generally, a fluid cannot be evenly flowed unless the pressure loss ofthe gap formed by the spacer 26 can be made approximately ten (10) timesor more the pressure loss of the discharge passage portion. For example,when the discharge gap 6 is 0.1 mm, a gap between the thickness of thespacer 26 and the discharge gap must be highly precise. It is extremelydifficult to manufacture the spacers 26 with this sort of precision anddispose them without contacting the discharge gap. For this reason, alarge cost increase is incurred in order to manufacture the spacers 26with good precision and inexpensive manufacture of the apparatus isimpossible.

Moreover, in the conventional ozonizer constructed such as above, theelectrode module including the pair of upper and lower low voltageelectrodes 7, the bilateral blocks 25 sandwiched between these lowvoltage electrodes 7, 7, the dielectric units 30 positioned at the innerside of the blocks 25, 25 and disposed between the low voltageelectrodes 7, 7, and the plurality of elastic spacers 26 for forming thedischarge gap(s) provided at both sides of the dielectric unit 30 forforming the discharge gaps 6 is laminated as a plurality via the lowvoltage electrodes 7 and is secured between the electrode presser plate22 provided on top and the base 24 provided at the bottom by theplurality of fastening bolts 21 as a fixing means passing through theelectrode module at both side portions thereof in the laminatingdirection. That is, since the structure is such that the dielectricmodule held between the low voltage electrodes 7 is fastened at bothends thereof, both sides of the electrode module become fulcrums and thelow voltage electrodes 7 which are supposed to be straight are deformedto a circular arc shape, and there is a problem in that, particularly ina discharge gap of 0.1 mm in thickness, the gap length cannot be evenand highly concentrated ozone cannot be obtained.

Further, a conventional ozone passage 8 is manufactured without beinggas sealed. Thus, 100% of the oxygen gas raw material cannot be suppliedto each electrode module sandwiched by the laminated low voltageelectrodes 7. That is, a “short pass phenomena” occurs in which oxygengas escapes directly to the ozone gas outlet without passing through thedischarge passage of the electrode module. When this “short passphenomena” takes place, the ozone generating efficiency of the electrodemodule is reduced and highly concentrated ozone cannot be generated;further, since the concentration of the ozone generated by the dischargegap 6 is diluted by a short pass fluid flow of the raw material oxygengas, there is a problem in that highly concentrated ozone gas cannot befurther derived.

SUMMARY OF THE INVENTION

The present invention was made to overcome all of the above mentionedproblems.

A first object of the present invention is to provide an ozonizer inwhich an electrode module construction has high reliability withoutdamaging ozone generating characteristics and, nevertheless, the life ofthe electrode module may be increased.

A second object of the present invention is to provide an ozonizer inwhich lamination of an extremely thin sheet-shaped electrode module maybe performed by means of a simple operation and further compactmodularization may be realized.

A third object of the present invention is to provide an ozonizer inwhich a construction of both a high voltage electrode 3 and a lowvoltage electrode 7 is capable of being cooled well.

A fourth object of the present invention is to provide an ozonizer inwhich a purity of generated ozone gas is high, that is, clean ozone gasmay be generated.

According to one aspect of the present invention there is provided anozonizer including a flat plate-shaped low voltage electrode, a flatplate-shaped high voltage electrode facing a main surface of the lowvoltage electrode, a flat plate-shaped dielectric and a spacer forforming a discharge gap of a thin thickness in a laminating directionprovided between the low voltage electrode and the high voltageelectrode. The ozonizer also includes an electrode cooling sheetprovided facing a main surface of the high voltage electrode at a sideopposite the discharge gap for cooling the high voltage electrode, athermal conducting/electric insulating sheet sandwiched between the highvoltage electrode and the electrode cooling sheet. An alternatingvoltage is applied between the low voltage electrode and the highvoltage electrode and a discharge is produced in the discharge gapinjected with oxygen gas to produce ozone gas.

Thus, the cooling efficiency of the discharge gaps is improved and thetemperature of the discharge gaps may be satisfactorily reduced.Accordingly, power density may be increased without decreasing ozonegenerating efficiency, and size reduction and cost reduction may beprovided for an apparatus in which it is possible to reduce the numberof electrode modules. Further, since the high voltage electrodes arecooled via the thermal conducting/electric insulating sheets, standardservice water may be used as cooling water without using ion exchangedwater and the like of small electric conductivity.

According to another aspect of the present invention there is providedan ozonizer including a flat plate-shaped low voltage electrode, a flatplate-shaped high voltage electrode is provided facing a main surface ofthe low voltage electrode. The ozonizer also includes a flatplate-shaped dielectric and a spacer for forming a discharge gap of athin thickness in a laminating direction provided between the lowvoltage electrode and the high voltage electrode, an electrode coolingsheet provided facing a main surface of the high voltage electrode at aside opposite the discharge gap for cooling the high voltage electrode.The ozonizer also includes a flexible thermal conducting/electricinsulating sheet sandwiched between the high voltage electrode and theelectrode cooling sheet. An alternating voltage is applied between thelow voltage electrode and the high voltage electrode and a discharge isproduced in the discharge gap injected with oxygen gas to produce ozonegas.

Thus, an electric conductivity monitoring device or ion exchanged watercirculating equipment and the like is unnecessary and, by reducing thenumber of apparatus components, it is possible provide for costreductions or reduce maintenance costs.

According to still another aspect of the present invention there isprovided an ozonizer including a flat plate-shaped low voltageelectrode, a flat plate-shaped high voltage electrode provided facingboth main surfaces of the low voltage electrode. The ozonizer alsoincludes a flat plate-shaped dielectric and a spacer for forming adischarge gap of a thin thickness in a laminating direction providedbetween the low voltage electrode and the high voltage electrode, anelectrode cooling sheet provided facing a main surface of the highvoltage electrode at a side opposite the discharge gap for cooling thehigh voltage electrode. The ozonizer also includes a thermalconducting/electric insulating sheet sandwiched between the high voltageelectrode and the electrode cooling sheet. The ozonizer also includes amanifold block provided between the low voltage electrode and theelectrode cooling sheet, and formed with a cooling water passageconnected with cooling water passages provided in the low voltageelectrode and the electrode cooling sheet, or formed with an ozone gaspassage connected with the ozone gas passage provided in the low voltageelectrode, both main surfaces of the low voltage electrode facing thedischarge gap are covered in an inorganic dielectric film. The ozonizeralso includes a main surface of the dielectric facing the high voltageelectrode coated with a conductive film having conductive properties,and the conductive film contacts the high voltage electrode, a flexiblethermal conducting sheet is sandwiched between the high voltageelectrode and the thermal conducting/electric insulating sheet and thethermal conducting/electric insulating sheet and the electrode coolingsheet, contacting each respectively. An alternating voltage is appliedbetween the low voltage electrode and the high voltage electrode and adischarge is produced in the discharge gap injected with oxygen gas toproduce ozone gas.

Thus, it is possible to form discharge gas for generating clean ozone inwhich metallic contamination does not develop and the cooling efficiencyof the discharge gaps 6 may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a typical explanatory drawing for explaining the ozonizer ofthe present invention;

FIG. 2 is a typical detailed cross sectional drawing of an ozonizerelectrode of an ozonizer of an Embodiment 1 of the present invention;

FIG. 3 is a top view of a low voltage electrode of an ozonizer of anEmbodiment 2 of the present invention;

FIG. 4 is cross sectional perspective view taken along the line A—A inFIG. 3;

FIG. 5 is a cross sectional perspective view taken along the line B—B inFIG. 3;

FIG. 6 is a top view of an electrode cooling sheet of an ozonizer of anEmbodiment 3 of the present invention;

FIG. 7 is cross sectional perspective view taken along the line C—C inFIG. 6;

FIG. 8 is cross sectional perspective view taken along the line D—D inFIG. 6;

FIG. 9 is a detailed cross sectional drawing of an ozonizer electrode ofan ozonizer of an Embodiment 5 of the present invention;

FIG. 10 is a top view of a low voltage electrode of an ozonizer of anEmbodiment 6 of the present invention;

FIG. 11 is cross sectional perspective view taken along the line E—E inFIG. 10;

FIG. 12 is cross sectional perspective view taken along the line F—F inFIG. 10;

FIG. 13 is a top view of a low voltage electrode of an ozonizer of anEmbodiment 7 of the present invention;

FIG. 14 is cross sectional perspective view taken along the line G—G inFIG. 13;

FIG. 15 is cross sectional perspective view taken along the line H—H inFIG. 13;

FIG. 16 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 8 of the present invention;

FIG. 17 is a side elevation of a high voltage electrode and a dielectricof an ozonizer of an Embodiment 9 of the present invention;

FIG. 18 is a drawing of a dielectric, as viewed from the top and asviewed from the side, of ozonizer of an Embodiment 10 of the presentinvention;

FIG. 19 is a side elevation of a high voltage electrode 3 and adielectric 5 of an ozonizer of an Embodiment 11 of the presentinvention;

FIG. 20 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 13 of the present invention;

FIG. 21 is a drawing of a thermal conducting sheet, as viewed from thetop and as viewed from the side, of ozonizer of an Embodiment 14 of thepresent invention;

FIG. 22 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 15 of the present invention;

FIG. 23 is a cross sectional drawing of a manifold block of an ozonizerof an Embodiment 16 of the present invention;

FIG. 24 is a top view of a low voltage electrode of an ozonizer of anEmbodiment 17 of the present invention;

FIG. 25 is cross sectional perspective view taken along the line I—I inFIG. 24;

FIG. 26 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 18 of the present invention;

FIG. 27 is a cross sectional drawing of a conventional ozonizer;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be explained below with reference to thedrawings.

FIG. 1 is a typical explanatory drawing for explaining a flat platelaminated ozone generating apparatus. The flat plate laminated ozonegenerating apparatus comprises an ozonizer 100 as an essentialconstruction for generating ozone, an ozone transformer 200 forsupplying power to the ozonizer 100 and a high frequency inverter 300.

The high frequency inverter 300 changes to a required frequency powerinput from a power source input 404 and outputs it to an inverter outputcable 403. The ozone transformer 200 increases this power to apredetermined voltage and supplies it as power necessary for generatingozone to the ozonizer 100. The high frequency inverter 300 further hasthe function of regulating current/voltage and controls a supplied powerinjection rate.

High voltage supplied from the ozone transformer 200 is supplied to highvoltage electrodes 3 of the ozonizer from a high voltage cable 401through a high voltage bushing 120. On the other hand, low voltage issupplied to a low voltage electrode 7 from a low voltage cable 402 via abase 24.

The ozonizer 100 includes a plurality of electrode modules 102comprising high voltage, electrodes 3 and a low voltage electrode 7. Apredetermined number of electrode modules 102 are laminated on the base24 in a direction of an arrow Z in the drawing to construct an ozonizerelectrode 101. The ozonizer electrode 101 is covered by a generatorcover 110. An ozonizer oxygen gas inlet 130 for supplying oxygen gasincluding trace amounts of nitrogen and carbon dioxide is provided atthe generator cover 110. The supplied oxygen gas impregnates thegenerator cover 110 and is entrapped in later-described discharge gaps.Meanwhile, an ozone gas outlet 11 for expelling ozone gas formed by theafter-described discharge gaps to outside from the ozonizer 100 and acooling water inlet/outlet 12 for bringing in and putting out coolingwater for cooling the electrode modules 102 are provided in the base 24.

In the flat plate laminated ozone generating apparatus constructed suchas above, the present invention particularly relates to the ozonizer 100which is an essential portion of the ozone generating apparatus, andspecifically, to a construction of a an ozonizer electrode 101 and anelectrode module 102 of the ozonizer 100.

Embodiment 1

FIG. 2 is a typical detailed cross sectional drawing of an ozonizerelectrode of an ozonizer of Embodiment 1 of the present invention. InFIG. 2, an ozonizer electrode 101 comprises a flat plate-shaped lowvoltage electrode 7, a flat plate-shaped high voltage electrode 3 facinga main surface of the low voltage electrode 7, a flat plate-shapeddielectric 5 and a spacer (not shown) for forming a discharge gap 6 of athin thickness in a laminating direction provided between the lowvoltage electrode 7 and the high voltage electrode 3.

The ozonizer electrode 101 further comprises an electrode cooling sheet1 provided facing a main surface of the high voltage electrode 3 at aside opposite the discharge gap 6 for cooling the high voltage electrode3, and a thermal conducting/electric insulating sheet 2 sandwichedbetween the high voltage electrode 3 and the electrode cooling sheet 1.

In the ozonizer electrode 101, an alternating voltage is applied betweenthe low voltage electrode 7 and the high voltage electrode 3 and adischarge is produced in the discharge gap 6 injected with oxygen gas toproduce ozone gas.

Power is supplied to a feed terminal 4 of the high voltage electrode 3from an ozone transformer 200 (shown in FIG. 2) via a high voltagebushing 120. The high voltage electrode 3 is made of a metal such asstainless steel, aluminum and the like. A main surface of the dielectric5 is adhered to the high voltage electrode 3. The dielectric 5 is madeof a material such as ceramic, glass, silicon and the like. A dischargegap 6 is formed between the dielectric 5 and low voltage electrode 7 bymeans of a later-described spacer. In the present embodiment, thedischarge gap 6 is formed in a disk shape and oxygen gas impregnated inthe generator cover 110 of FIG. 1 is injected from an entire peripheryof the discharge gap 6 toward a central direction.

Oxygen gas flowing in the discharge gap 6 is converted to ozone byapplying an alternating voltage between the low voltage electrode 7 andthe high voltage electrode 3. The ozone gas converted to ozonifiedoxygen by the discharge gap 6 is led to the ozone gas outlet 11 from acentral portion of the low voltage electrode 7 via an ozone gas passage8 provided in the low voltage electrode 7.

The low voltage electrode 7 is a thin sheet-shaped conductive rigid bodycomprising two (2) conductive plates, such as stainless steel plates andthe like, joined so as to form the ozone gas passage 8 there-between. Acooling water passage 9 for increasing an ozone generating efficiency isprovided in the low voltage electrode 7 in addition to the ozone gaspassage(s) 8. A gas temperature in the discharge gap 6 is lowered byflowing cooling water in the cooling water passage 9.

The high voltage electrode 3 is disposed at a main surface of the lowvoltage electrode 7 at a side opposite the discharge gap 6 via thethermal conducting/electric insulating sheet 2. Thus, the low voltageelectrode 7 cools the high voltage electrode 3 in addition to thedischarge gap 6. Also, a water cooling type electrode cooling sheet 1 isdisposed at an uppermost high voltage electrode 3 via the thermalconducting/electric insulating sheet 2. The electrode cooling sheet 1 isa thin sheet-shaped rigid body comprising two (2) steel plates, such asstainless steel plates and the like, joined so as to form a coolingwater passage 9 there-between. That is, the cooling water passage 9 isalso formed in the electrode cooling sheet 1 and cooling water flows inthis cooling water passage 9.

The ozone gas passage 8 formed in the low voltage electrode 7 isconnected to the ozone gas outlet 11 provided in the base 24 via anozone gas passage 8 formed in a manifold block 23. On the other hand,the cooling water passages 9 formed in the electrode cooling sheet 1 andlow voltage electrode 7 are connected to the cooling water inlet/outlet12 provided in the base 24 via a cooling water passage 9 formed in themanifold block 23.

Although not specifically shown in the drawings, a gasket material, suchas an O-ring and the like, is sandwiched between the electrode coolingsheet 1 or low voltage electrode 7 and manifold block 23 or base 24 forwater-tightness of the cooling water. Moreover, a gasket material, suchas an O-ring and the like, is also sandwiched for air-tightness of theozone gas.

An electrode module(s) 102 comprising the low voltage electrode 7, highvoltage electrode 3, dielectric 5, spacer, electrode cooling sheet 1 andthermal conducting/electric insulating sheet 2 is fastened and fixedbetween an electrode presser plate 22 and the base 24 by fastening bolts21 passing through each structural element. The discharge gaps 6 aremaintained at a predetermined thickness in the laminating direction bymeans of the manifold block 23.

Moreover, in the present embodiment, the dielectric 5, necessary forsilent (dielectric barrier) discharge, is provided between the lowvoltage electrode 7 and high voltage electrode 3 and the spacer isdisposed between this dielectric 5 and the low voltage electrode 7 toprovide the discharge gap 6. However, the spacer may also be disposedbetween the high voltage electrode 3 and the dielectric 5 to provide thedischarge gap 6.

Next, operation will be explained, when an alternating voltage isapplied between the low voltage electrode 7 and the high voltageelectrode 3 a silent (dielectric barrier) discharge is produced by thedischarge gap 6. When oxygen gas is passed in the discharge gap 6, theoxygen is converted and ozone is produced. The oxygen gas impregnatingthe generator cover 110 passes through the discharge gap 6 formedbetween the low voltage electrode 7 and dielectric 5 and in this courseis converted to ozone. In the present embodiment, the high voltageelectrode 3, dielectric 5 and discharge gap 6 formed there-between areeach formed in a an approximate disk shape. The oxygen gas flows from anentire periphery of the dielectric 5 toward a center and becomesozonified oxygen gas in the discharge gaps 6.

In order to efficiently create ozone it is necessary that the dischargegap 6, which is a space of particularly thin thickness, be preciselymaintained. The electrode module laminated body is fastened between theelectrode presser plate 22 and the base 24 by means of the plurality offastening bolts 21 disposed in the blocks 23 and passing through bothside portions thereof in the laminating direction so as to obtain apredetermined gap precision. The discharge gap(s) 6 is formed by meansof discharge gap spacers (not shown) disposed at a surface of the lowvoltage electrode 7. That is to say, a thickness of the discharge gap 6(height in the laminating direction) is set by a height of thesedischarge gap spacers. The precision of the discharge gaps 6 ismaintained by uniformly processing the height of the discharge gapspacers and by fastening each electrode with the fastening bolts 21.

As an additional means for efficiently creating ozone, a method forlowering a temperature inside the discharge gaps 6 may be given. Amethod is conceived wherein the high voltage electrode 3 and low voltageelectrode 7 are provided as electrodes and both these electrodes arecooled with water or gas and the like. Although, between water and gas,a cooling effect is greater with water, in a case where water is used itis necessary to decrease an electric conductivity (use ion exchangedwater etc.) of the cooling water because a high voltage is applied atthe high voltage electrode 3. On the other hand, although there is anadvantage in that this is not necessary in a case where gas is used,there are disadvantages in that the construction becomes complicated andthere is a lot of noise or a heat capacity of the coolant is small.

In the present embodiment, the discharge gaps 6 are formed adjacent tothe low voltage electrode 7 and the discharge gaps 6 are cooled byproviding cooling water passages 9 in the low voltage electrode 7.Moreover, the electrode cooling sheets 1 are provided, via the thermalconducting/electric insulating sheets 2, for cooling the high voltageelectrodes 3, and thus a structure is such that heat of the high voltageelectrodes 3 is vented. Heat generated by the high voltage electrodes 3passes through the thermal conducting/electric insulating sheets 2having high thermal conductivity and excellent electric insulatingcharacteristics and is cooled by means of the low voltage electrode 7heat sinked by the cooling water. Moreover the uppermost (high voltageelectrode 3) is cooled by means of the electrode cooling sheet 1. Hence,it is possible to keep the gas temperature of the discharge gaps 6 lowby simultaneously cooling the high voltage electrodes 3 and low voltageelectrode 7.

Furthermore, since a construction is such that the high voltageelectrode 3 may be cooled by the low voltage electrode 7 via the thermalconducting/electric insulating sheet 2 and the, uppermost (high voltageelectrode 3) may be cooled by the electrode cooling sheet 1, it is notnecessary to lower the electric conductivity of the cooling waterflowing in the low voltage electrode 7 and electrode cooling sheet 1 andstandard service water may be used. Thus, there is also an advantage inthat the cooling water may be common with that for cooling the lowvoltage electrode 7.

Accordingly, in the present embodiment, the cooling efficiency of thedischarge gaps 6 is improved and the temperature of the discharge gaps 6may be satisfactorily reduced. Thus, power density may be increasedwithout decreasing ozone generating efficiency, and size reduction andcost reduction may be provided for in an apparatus in which it ispossible to reduce the number of electrode modules. Further, since thehigh voltage electrodes 3 are cooled via the thermal conducting/electricinsulating sheets 2, standard service water may be used as cooling waterwithout using ion exchanged water and the like of a small electricconductivity. Thus, an electric conductivity monitoring device or ionexchanged water circulating equipment and the like is unnecessary and,by reducing the number of apparatus components, it is possible toprovide for cost reductions or reduce maintenance costs.

Embodiment 2

FIG. 3 is a top view of a low voltage electrode 7 of an ozonizer ofEmbodiment 2 of the present invention. FIG. 4 is cross sectionalperspective view taken along the line A—A in FIG. 3. FIG. 5 is crosssectional perspective view taken along the line B—B in FIG. 3. As shownin FIGS. 4 and 5, the low voltage electrode 7 is constructed from two(2) metal electrodes, an upper low voltage electrode 7a and a lower lowvoltage electrode 7b. Grooves of several mm in depth are formed byetching or machining in advance a main surface of the two electrodes 7a,7b. Then, the two electrodes 7a, 7b are adhered such that these groovesline up to produce the low voltage electrode 7. The lined up groovesform an ozone gas passage 8 and cooling water passage(s) 9 inside thelow voltage electrode 7.

Furthermore, an ozone gas passage 8 and cooling water passage 9extending in the laminating direction are formed in an ozone gas/coolingwater deriving portion 900 at one end portion (left side in FIG. 3) ofthe low voltage electrode 7. Here, the cooling water passage 9 isdivided into a cooling water inlet 9a and a cooling water outlet 9b. Thecooling water passage(s) 9 connected to the cooling water inlet 9a andcooling water outlet 9b is formed over an approximate entirely insidethe low voltage electrode 7, as shown by the dotted line in FIG. 3. Thatis, they are formed as a plurality of concentric disk shapes from acenter to a peripheral portion in an approximately disk-shaped lowvoltage electrode discharge portion 700. Moreover, adjacent concentricdisk-shaped cooling water passages 9 are partitioned by ribs of a thinwidth. On the other hand, the ozone gas passage 8 formed inside the lowvoltage electrode 7 extends from the passage extending in the laminatingdirection at the end portion to the central portion and is connected toan opening formed in one side main surfaces at the central portion.

The ozone gas passage 8 extending in the laminating direction andprovided at the end portion of the low voltage electrode 7 and thecooling water passages 9 are connected with the ozone gas passage andcooling water passage formed in the manifold block 23 and finallyconnected to the ozone gas outlet 11 and cooling water outlet/inlet 12provided in the base 24.

A plurality of round convex portions for forming the discharge gaps 6are formed by similar etching or machining over entire main surfaceswhich are at opposite sides of the surfaces where grooves are formed forforming the ozone gas passage 8 and cooling water passages 9 of theupper side electrode 7a. The above ozone gas passage 8 is communicatedwith the opening formed in the surface for forming the discharge gaps 6.

Generated ozone gas is led from the central portion of the low voltageelectrode 7 through the ozone gas passage 8 provided in the low voltageelectrode 7 to the ozone gas passage 8 extending in the laminatingdirection in the ozone gas/cooling water deriving portion 900 of one endportion of the low voltage electrode 7. On the other hand, cooling waterflowing throughout the whole interior of the low voltage electrode 7enters the low voltage electrode 7 from a cooling water inlet opening 9aof the ozone gas/cooling water deriving portion 900 and cools the entiresurface(s) of the low voltage electrode discharge portion 700 and comesout the cooling water outlet opening 9b of the ozone gas/cooling waterderiving portion 900.

The collection of ozone gas outlets and collective structure ofinlets/outlets of cooling water in the ozone gas/cooling water derivingportion 900 at the end portion of the low voltage electrode 7 isconnected to the ozone gas outlet 11 and cooling water inlet/outlet 12,respectfully, provided in the base 24 in cooperation with the manifoldblocks 23 provided adjacent to the low voltage electrode 7. Thus, in thepresent embodiment, collective coupling and piping members areeliminated by forming passages in the low voltage electrode 7 andmanifold block 23 and a compact and simplified ozonizer is realized byreducing the space for these coupling and piping members.

Accordingly, in the present embodiment, an airtight circulating space isconstructed by adhering together at least two (2) metal plates withconvexoconcave processing within several mm by etching or machining thelow voltage electrode 7, and because the ozone gas passage 8 and thecooling water passages 9 are formed so as to be separated in an airtightmanner, it is possible to decrease the thickness of the low voltageelectrode 7 and reduce the size of the apparatus. Furthermore, sincepiping for deriving cooling water and ozone is unnecessary, assembly anddisassembly may be simply performed and a low cost ozonizer may beprovided.

Moreover, in the present embodiment, although the low voltage electrode7 is made by joining together two (2) electrodes 7a, 7b, three (3) ormore electrodes may also be joined to form an ozone gas passage 8 andcooling water passages 9 at an inside portion thereof.

Also, in the present embodiment, although the discharge gap 6 isprovided between the low voltage electrode 7 and dielectric 5 and theozone gas passage 8 is formed inside the low voltage electrode 7, adischarge gap may be provided between the high voltage electrode 3 anddielectric 5 and an ozone gas passage may be formed inside the highvoltage electrode 3.

Embodiment 3

FIG. 6 is a top view of an electrode cooling sheet 1 of an ozonizer ofan Embodiment 3 of the present invention. FIG. 7 is cross sectionalperspective view taken along the line C—C in FIG. 6. FIG. 8 is crosssectional perspective view taken along the line D—D in FIG. 6. As shownin FIGS. 7 and 8, the electrode cooling sheet 1 is constructed from two(2) metal sheets, an upper electrode cooling sheet 1a and a lowerelectrode cooling sheet 1b. Grooves of several mm in depth are formed byetching or machining in advance a main surface of the two metal sheets1a, 1b. Then, the two metal sheets 1a, 1b are adhered such that theregrooves line up to produce the electrode cooling sheet 1. The lined upgrooves form cooling water passages 9 inside the electrode cooling sheet1.

An ozone gas passage 8 and cooling water passage 9 extending in thelaminating direction are formed at an end portion (left side in FIG. 3)of the electric cooling sheet 1, as in the ozone gas/cooling waterderiving portion 900 of the low voltage electrode 7 of Embodiment 2.Here, the cooling water passage 9 is divided into a cooling water inlet9a and a cooling water outlet 9b. The cooling water passage(s) 9connected to the cooling water inlet 9a and cooling water outlet 9b isformed over an approximate entirety inside the electrode cooling sheet1, as shown by the dotted line in FIG. 6. That is, they are formed as aplurality of concentric disk shapes from a center to a peripheralportion in an approximately disk-shaped main portion. Moreover, adjacentconcentric disk-shaped cooling water passages 9 are partitioned by ribsof a thin width.

The ozone gas passage 8 extending in the laminating direction andprovided at the end portion of the electrode cooling sheet 1 and thecooling water passages 9 are connected with an ozone gas passage andcooling water passage formed in the manifold block(s) 23 and finallyconnected to the ozone gas outlet 11 and cooling water outlet/inlet 12provided in the base 24.

Accordingly, in the present embodiment, since an airtight circulatingspace is constructed by adhering together at least two (2) metal sheetswith convexoconcave processing within several mm by etching or machiningthe electrode cooling sheet 1 and the cooling water passages 9 areformed, it is possible to decrease the thickness of the electrodecooling sheet 1 and reduce the size of the apparatus. Furthermore, sincepiping for deriving cooling water and ozone is unnecessary, assembly anddisassembly may be simply performed and a low cost ozonizer may beprovided.

Moreover, in the present embodiment, although the electrode coolingsheet 1 is made by joining together two (2) metal sheets 1a, 1b, three(3) or more sheets may also be joined to form an ozone gas passage 8 andcooling water passages 9 at an inside portion thereof.

Embodiment 4

The present embodiment relates to a method of joining metal plates. As acommon method for joining the two (2) metal plates 1a, 1b, a brazingmethod using a brazing filler as a bonding agent may be given.Incidentally, because ozone circulates in the ozone gas passage 8, theozone gas causes an oxidation reaction with the brazing filter and thisproduces adverse phenomena for the ozonizer such as ozone gasdecomposition, the creation of oxides and the like. Here, in the presentinvention, this common brazing method is not employed.

That is to say, this common brazing method is not used in joining thetwo electrodes 7a, 7b of Embodiment 2 and the two metal plates 1a, 1b ofEmbodiment 3. In the present embodiment, a heating/pressure type joiningmethod is used for joining the two metal plates. In this method, twometal plates are pressed together in the laminating direction with alarge pressure while heating and the metal (plates) are fused at theircontact surfaces to be joined together. The metal is melted at theparticular melting point of the metal. Thus, it is possible to join themetal by means of a predetermined heat and predetermined pressure whichare determined by the joining material. Another bonding agent is alsonot used at all, to say nothing of brazing filler. Thus, it is possibleto generate clean ozone without producing an oxide reactant due toozone.

Accordingly, in the present invention, since the joining method used foradhering two or more metal plates joins by means of heat and pressureonly, without using a bonding agent, ozone caused corrosion of thebonding agent does not occur and it is possible to realize an ozonizerhaving a long life and high reliability.

Embodiment 5

FIG. 9 is a detailed cross sectional drawing of an ozonizer electrode ofan ozonizer of an Embodiment 5 of the present invention. In the presentinvention, an entire discharge surface of the low voltage electrode 7facing the discharge gap 6 is covered with a dielectric film 13 of aninorganic material. This dielectric film 13 faces the discharge gap 6. Athickness of the dielectric film 13 is sufficient to block metal ions.

In an ozonizer constructed such as above, both surfaces of the dischargegap 6 for producing a silent discharge are enclosed with the inorganicmaterial, and clean ozone without metallic contamination may begenerated by passing oxygen gas through this gap.

Embodiment 6

FIG. 10 is a top view of a low voltage electrode 7 of an ozonizer of anEmbodiment 6 of the present invention. FIG. 11 is cross sectionalperspective view taken along the line E—E in FIG. 10. FIG. 12 is crosssectional perspective view taken along the line F—F in FIG. 10. In thepresent embodiment, an entire discharge surface of the low voltageelectrode 7 facing the discharge gap 6 is covered with a ceramicdielectric film 13a. The ceramic dielectric film 13a faces the dischargegap 6. A plurality of small, disk-shaped, ceramic dielectric dischargegap spacers 13a1 for forming the discharge gap 6 are disposed on theceramic dielectric film 13a.

In an ozonizer constructed such as above, oxygen gas flows into thedischarge gap 6 from an outer periphery of the low voltage electrode 7and ozone is formed by means of a silent discharge while the oxygen gaspasses between the ceramic dielectric discharge gap spacers 13a1, andthe ozone passes through an inner portion of the low voltage electrode 7and flows out to the outside by means of an ozone gas passage 8 formedin a central portion of the low voltage electrode 7. At this time,because the spacers are also an inorganic material, in addition to bothsurfaces enclosing the discharge gap 6 with the inorganic material, afurther clean ozone without metallic contamination may be generated.

Moreover, the ceramic dielectric film 13a is formed by a thermalspraying technique and thickness thereof is controlled to several μm.Further, according to this thermal spraying technique, it is alsopossible form the ceramic dielectric discharge gap spacers 13a1concurrently.

Embodiment 7

FIG. 13 is a top view of a low voltage electrode 7 of an ozonizer of anEmbodiment 7 of the present invention. FIG. 14 is cross sectionalperspective view taken along the line G—G in FIG. 13. FIG. 15 is crosssectional perspective view taken along the line H—H in FIG. 13. In thepresent embodiment, an entire discharge surface of the low voltageelectrode 7 facing the discharge gap 6 is covered with a glassdielectric film 13b. The glass dielectric film 13b faces the dischargegap 6. A plurality of small, disk-shaped, glass dielectric discharge gapspacers 13b1 for forming the discharge gap 6 are disposed on the glassdielectric film 13b.

In an ozonizer constructed such as above, oxygen gas flows into thedischarge gap 6 from an outer periphery of the low voltage electrode 7and ozone is formed by means of a silent discharge while the oxygen gaspasses between the glass dielectric discharge gap spacers 13b1, and theozone passes through an inner portion of the low voltage electrode 7 andflows out to the outside by means of an ozone gas passage formed in acentral portion of the low voltage electrode 7. At this time, becausethe spacers are also an inorganic material, in addition to both surfacesenclosing the discharge gap 6 with the inorganic material, a furtherclean ozone without metallic contamination may be generated.

Moreover, in making the glass dielectric film 13b, first, a glass plateof a quartz material is subjected to a shot blasting treatment-using amask and the convex glass dielectric discharge gap spacers 13b1 areformed. Then, the glass dielectric film 13b is adhered to the lowvoltage electrode 7 by means of an adhesive 13b2.

Embodiment 8

FIG. 16 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 8 of the present invention. In thepresent embodiment, a main surface of the dielectric 5 at the highvoltage electrode 3 side is covered all over with a conductive film 14.

In a case where the conductive film 14 is not provided, when a surfaceof the high voltage electrode 3 and a surface of the dielectric 5 arepressed together by mechanical pressure only without using an adhesiveor the like, the surface of the high voltage electrode 3 and surface ofthe dielectric 5 cannot be closely contacted. A gap develops in oneportion of a contact surface(s) and an improper discharge (localdischarge) occurs in this gap. This improper discharge is a problem inthat it damages the dielectric 5, degrades the ozone generatingefficiency and interferes with the generation of clean ozone.

In the present embodiment, by applying the conductive film 14 on thesurface of the dielectric 5, even if, for example, the contact surfacescannot be completely closely joined and a gap develops in one portion ofthe contact surfaces, since the conductive film 14 of the dielectric 5and high voltage electrode 3 have the same electric potential, it ispossible to prevent an improper discharge, and it is possible to preventthe occurrence of metallic contamination.

Embodiment 9

FIG. 17 is a side elevation of a high voltage electrode 3 and adielectric 5 of an ozonizer of an Embodiment 9 of the present invention.In the present embodiment, the high voltage electrode 3 and dielectric 5are joined together so that there are no gaps there-between by means ofa conductive adhesive. In this sort of construction as well, it ispossible to increase adhesion between the high voltage electrode 3 anddielectric 5, an improper discharge may be prevented and it is possibleto prevent the occurrence of metallic contamination. Furthermore,positioning adjustments and the like are unnecessary and assembly isfacilitated.

Embodiment 10

FIG. 18 is a drawing of a dielectric 5, as viewed from the top and asviewed from the side, of ozonizer of an Embodiment 10 of the presentinvention. The present embodiment includes a metallic contaminationsuppressing construction at an edge portion of the conductive film 14.When a high voltage electric potential is applied to the conductive film14, an abnormal corona discharge occurs at an edge portion thereof. Thisabnormal corona discharge causes metallic contamination. In the presentembodiment, an insulating film 16 is coated all around a portion formedby a step of an outer circumferential portion of the conductive film 14.Hence, it is possible to prevent the abnormal corona discharge fromoccurring at the edge portion and it is possible to prevent theoccurrence of metallic contamination.

Other constructions are similar to Embodiment 8.

Embodiment 11

FIG. 19 is a side elevation of a high voltage electrode 3 and adielectric 5 of an ozonizer of an Embodiment 11 of the presentinvention. In the present embodiment, an insulating film 16 is coatedall around a portion formed by a step of an outer circumferentialportion of the conductive adhesive 15. Thus, it is possible to preventthe abnormal corona discharge from occurring at the edge portion of theconductive adhesive 15 and it is possible to prevent the occurrence ofmetallic contamination.

Other constructions are similar to Embodiment 9.

Embodiment 12

In the present embodiment, an outside diameter of the high voltageelectrode 3 is smaller than an outside diameter of the dielectric 5 andsmaller than an outside diameter of the conductive film 14 provided on asurface of the dielectric 5. Other constructions are similar toEmbodiment 8.

By making the outside diameter of the high voltage electrode 3 smallerthan the outside diameter of the dielectric 5 and the conductive film14, the abnormal corona discharge is done away with and metalliccontamination may be prevented. In a case where the outside diameter ofthe conductive film 14 is smaller than the high voltage electrode 3, adischarge occurs between the high voltage electrode 3 and dielectric 5and causes metallic contamination.

Embodiment 13

FIG. 20 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 13 of the present invention. In thepresent embodiment, thermal conductive sheets 17, each made of amaterial having excellent elasticity and high thermal conductivity, forexample, silicon gum and the like, are sandwiched between the highvoltage electrode 3 and the thermal conducting/electric insulating sheet2 and the low voltage electrode 7 and the thermal conducting/electricinsulation sheet 2. Other constructions are similar to Embodiment 1.

In cooling a high voltage portion, heat generated from the high voltageelectrode 3 is let off from the low voltage electrode 7 via the thermalconducting/electric insulating sheet 2. Moreover, the uppermost (highvoltage electrode 3) is cooled by means of the electrode cooling sheet1. Depending on the manufacturing precision of each contact surface ofthe high voltage electrode 3, electrode cooling sheet 1 and thermalconducting/electric insulating sheet 2, it is possible for a gap tooccur between the high voltage electrode 3 and the thermalconducting/electric insulating sheet 2 and the low voltage electrode 7and the thermal conducting/electric insulating sheet 2 and the electrodecooling sheet 1 and the thermal conducting/electric insulating sheet 2.The existence of the gap of oxygen gas of extremely low thermalconductivity greatly increases thermal resistance. Thus, this gap mustbe eliminated in order for cooling of the high voltage electrode 3 to beefficiently performed.

Since the thermal conductive sheets 17 of the present embodiment aremade of a material having excellent elasticity and high thermalconductivity, a gap occurring due to an variance in manufacturingprecision may be eliminated, the generated heat of the high voltageelectrodes may be transferred to the low voltage electrode 7 or theelectrode cooling sheet 1 and the temperature of the high voltageelectrode 3 may be favorably lowered.

Accordingly, in the present embodiment, minute gaps between the highvoltage electrode 3 and the thermal conducting/electric insulating sheet2 and the electrode cooling sheet 1 and the thermal conducting/electricinsulating sheet 2 are eliminated, it is possible to eliminate minutegaps which degrade thermal conductivity, the thermal conductivitybetween the high voltage electrode 3 and cooling sheet 1 is improved,the cooling efficiency of the discharge gaps 6 is improved, thetemperature of the discharge gaps 6 may be favorably lowered and theozone generating efficiency is improved. Furthermore, because thethermal conductive sheets 17 have elasticity, there is also an excellentgas shielding effect by pressing from both sides with a predeterminedpressure.

Moreover, the thermal conductive sheet 17 is not limited to silicon gum,the stated effects may be obtained as long as it is a material havingexcellent elasticity and high thermal conductivity.

Embodiment 14

FIG. 21 is a drawing of a thermal conducting sheet 17, as viewed fromthe top and as viewed from the side, of ozonizer of an Embodiment 14 ofthe present invention. In the thermal conducting sheet 17 of the presentembodiment, a ceramic powder 18 is applied all over both main surfacesthereof. Other constructions are the same as in Embodiment 13.

It is necessary that thermal conducting sheet 17 be elastic, haveexcellent thermal conductivity, and excellent workability. In thisregard, silicone gel is an optimal material. Silicone gel has hightackiness and where it is applied between the high voltage electrode 3and the thermal conducting/electric insulating sheet 2 and electrodecooling sheet 1, there is a problem in production in that air bubbles(minute air gaps) are entrapped at a contact surface. As stated above,cooling efficiency is degraded when gaps develop. In order to resolvethis problem, in the present embodiment, the ceramic powder 18 isapplied to the thermal conducting sheet 17. The tackiness of the sheetis eliminated when ceramic powder 18 is lightly sprayed on to the tackysheet. Thus, the thermal conducting sheet 17 may be easily appliedwithout bubbles developing.

Accordingly, in the present embodiment, since a silicon gel having theceramic powder 18 applied to a surface thereof is used as the thermalconducting sheet 17 of Embodiment 13, the tackiness of the thermalconducting sheet 17 is suppressed, air bubbles may be easily eliminatedbetween the high voltage electrode 3 and thermal conducting/electricinsulating sheet 2 and electrode cooling sheet 1, mounting of thethermal conducting sheet 17 is facilitated and it is possible to providea low-cost ozonizer.

Embodiment 15

FIG. 22 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 15 of the present invention. In thepresent embodiment, a thermal conducting/electric insulating sheet 19made of a material having excellent elasticity and high thermalconductivity, for example, silicon gum and the like is sandwichedbetween the high voltage electrode 3 and the electrode cooling sheet 1.That is, the thermal conducting/electric insulating sheet 19 issandwiched between the high voltage electrode 3 and the electrodecooling sheet 1 instead of the thermal conducting/electric insulatingsheet 2 of Embodiment 1.

The functions sought for the material between the high voltage electrode3 and the electrode cooling sheet 1 are an insulating function capableof insulating (against) high voltage electricity and a thermalconducting function for efficiently transferring heat. In addition tothese two characteristics the thermal conducting/electric insulatingsheet 19 of the present embodiment also has excellent flexibility. Gapsmay be eliminated between the high voltage electrode 3 and the electrodecooling sheet 1, heat of the high voltage electrode 3 may be transferredto the electrode cooling sheet 1 and a temperature of the high voltageelectrode 3 may be favorably lowered. In addition, the thermalconducting/electric insulating sheet 2 of Embodiment 1 may be omitted,and it is possible to reduces the number of components and reduce sizeand cost.

Namely, in the present embodiment, in the ozonizer of Embodiment 1,since the construction is such that the thermal conducting/electricinsulating sheet 19 of excellent elasticity and having an insulatingfunction and thermal conducting function is sandwiched between the highvoltage electrode 3 and the electrode cooling sheet 1 instead of thethermal conducting/electric insulating sheet 2, it is possible to reduceby one (1) the three (3) components, i.e., the thermal conducting sheet17, the thermal conducting/electric insulating sheet 2 and the thermalconducting sheet 17 and the cost of the apparatus may be reduced.

Embodiment 16

FIG. 23 is a cross sectional drawing of a manifold block 23 of anozonizer of an Embodiment 16 of the present invention. The manifoldblock 23 is divided into two (2) members in a laminating direction, thatis, an upper manifold block 23a and a lower manifold block 23b. An ozonegas passage 8 and cooling water passage 9 are formed in both so as topass therethrough in a laminating direction. The ozone gas passage(s) 8and cooling water passage(s) 9 are connected to the ozone gas passages 8and cooling water passages 9 provided in the high voltage electrode 7and electrode cooling sheet 1.

Cylindrical portions which extend toward the top-side of the drawing andprovided so as to enclose the ozone gas passage 8 and cooling waterpassage 9 are formed on the lower manifold block 23b. On the other hand,the upper manifold block 23a includes concave portions into which thesecylindrical portions are inserted. The ozone gas passage 8 and coolingwater passage 9 are formed in a central portion of these concaveportions. The cylindrical portions and concave portions are engagedhaving a gap which allows for sliding in the laminating direction, so asto have a cylinder and piston relationship. O-rings 23c for maintainingair-tightness are disposed between the cylindrical portions and concaveportions. Also, a disc spring 23d is disposed between the upper manifoldblock 23a and lower manifold block 23b so as to have elasticity in thelaminating direction. The manifold blocks 23 of the present invention,being of such a construction, include passages extending in thelaminating direction connected to the ozone gas passages 8 and coolingwater passages 9 provided in the low voltage electrode 7 and electrodecooling sheet 1 and may expand and contract in the laminating directionof the electrodes.

As mentioned in Embodiment 1 for instance, the precision of thedischarge gap 6 must be increased in order to improve ozone generatingefficiency. Hence, the precision of the discharge gaps 6 is improved byincreasing the height-precision of the discharge gap forming spacers andfastening the electrode as a whole to the base 24 by means of thepresser plate 22 and the fastening bolts 21. Nevertheless, the lowvoltage electrode 7 and electrode cooling sheet 1 are provided adjacentto the manifold block 23 and an adverse influence acts on the electrodefastening when there is a strong joining strength with the manifoldblock 23 and there is a concern that the precision of the discharge gaps6 will not be maintained.

Namely, in Embodiment 2 and with reference to FIG. 2, starting with thehigh voltage electrode 3 and low voltage electrode 7 many members arelaminated and fastened to the base 24 by means of the fastening bolts21. In this laminate, the discharge gaps 6 are formed by discharge gapforming spacers. Meanwhile, since many members are laminated in thelaminate, errors in each of the members accumulate and a certain errordevelops in the longitudinal direction. The electrode cooling sheet 1and low voltage electrode 7 are, for example, rigid bodies made ofstainless steel and the like. Thus, no matter how precisely the blocksandwiched between the electrode cooling sheet 1 and low voltageelectrode 7 is manufactured, the electrode cooling sheet 1 and lowvoltage electrode 7 are distorted by the error in the longitudinaldirection of the laminate. The occurrence of this distortion makes itimpossible to precisely form the discharge gaps 6. In comparison, themanifold block 23 of the present embodiment is of construction havingelasticity in the laminating direction of the electrodes. Thus, an errorin the longitudinal direction of the laminate may be absorbed and it ispossible to precisely form the discharge gaps 6.

Accordingly, in the present embodiment, because there is provided themanifold block 23 formed with the cooling water passage 9 or ozone gaspassage 8 connected to the cooling water passages 9 or ozone gaspassages 8 provided in each electrode, respectfully, the space providedfor piping for cooling water and for piping for deriving ozone gas maybe reduced, and it is possible decrease the size of the apparatus,reduce the weight and reduce the number of components and it is possibleto provide for increased quality of the apparatus.

Also, the manifold block 23 of the present embodiment is of aconstruction having elasticity in the laminating direction of theelectrodes. Thus, it is possible to eliminate the adverse influence onthe gap length of the discharge gap caused by the fastening of themanifold block 23 and the precision of the discharge gaps may beimproved.

Embodiment 17

FIG. 24 is a top view of a low voltage electrode 7 of an ozonizer of anEmbodiment 17 of the present invention. FIG. 25 is cross sectionalperspective view taken along the line I—I in FIG. 24. The presentembodiment relates to disposition of discharge gap spacers 7c. Groovesof several mm in depth are formed by etching or machining in advance onemain surface of two electrodes 7a, 7b. These grooves are lined up toform an ozone gas passage 8 and cooling water passage(s) 9. Ribs 7d forseparating passages are provided between adjacent grooves. The dischargegap spacers 7c of the present embodiment are disposed at a positionopposite the ribs 7d. That is to say, the discharge gap spacer(s) 7c isdisposed on a surface of the low voltage electrode 7 facing thedischarge gap 6 at a position which passes through the rib 7d in thelaminating direction.

Cooling water passages 9 are formed around an entire surface inside thelow voltage electrode 7. A thickness of the ribs 7d for separating thepassages is made as thin as possible in order to increase a surface areaof the cooling water passages 9 even a little. On the other hand, adiameter of the discharge gap spacers 7c for forming the discharge gaps6 is preferably as small as possible to increase the discharge gaps 6.The low voltage electrode 7 is, as a whole, a thin rigid body made ofstainless steel and the like and in a case where pressure increases inthe laminating direction, although the portions having the ribs 7d arestrong against deformation, the locations without the ribs 7d are weak.That is, they are recessed. Since the discharge gap spacers 7c of thepresent embodiment are disposed at a position opposite the ribs 7d,there is accordingly almost no deformation of the low voltage electrode7. Consequently, deformation of the discharge gaps 6 may be suppressedand it is possible to form highly precise discharge gaps 6.

Accordingly, in the present embodiment, the discharge gap spacers 7c aredisposed at positions opposite the ribs 7d forming the cooling waterpassages 9 of the low voltage electrode 7. Thus, the low voltageelectrode 7 is not deformed and the adverse influence on the dischargegaps 6 due to fastening the electrodes may be eliminated and the ozonegenerating efficiency increased.

Embodiment 18

FIG. 26 is a detailed cross sectional drawing of an ozonizer electrodeof an ozonizer of an Embodiment 18 of the present invention. The presentembodiment includes the construction of Embodiment 5 wherein the entiredischarge surface of the low voltage electrode 7 facing the dischargegap 6 is covered with the dielectric film 13 of an inorganic material,the construction of Embodiment 8 wherein the main surface of thedielectric 5 at the high voltage electrode 3 side is covered all overwith the conductive film 14 and the construction of Embodiment 13 inwhich the thermal conductive sheet 17 is sandwiched between each of thehigh voltage electrode 3, thermal conducting/electric insulating sheet 2and the electrode cooling sheet 1.

Hence, it is possible to form discharge gaps 6 for generating cleanozone in which metallic contamination does not develop and the coolingefficiency of the discharge gaps 6 may be improved.

Embodiment 19

The present embodiment will be explained using FIGS. 1 and 2. In anozonizer electrode 101 of the present embodiment, a total of eight (8)electrode modules 102 comprising, as shown in FIG. 2, a flatplate-shaped low voltage electrode 7, a flat plate-shaped high voltageelectrode 3 facing a main surface of the low voltage electrode 7, a flatplate-shaped dielectric 5 and a spacer (not shown) for forming adischarge gap 6 of a thin thickness in a laminating direction providedbetween the low voltage electrode 7 and the high voltage electrode 3, anelectrode cooling sheet 1 provided facing a main surface of the highvoltage electrode 3 at a side opposite the discharge gap 6 for coolingthe high voltage electrode 3, and a thermal conducting/electricinsulating sheet 2 sandwiched between the high voltage electrode 3 andthe electrode cooling sheet 1, are laminated as shown in FIG. 1, i.e.,N-1, N-2, N-3 . . . N-7, N-8.

Accordingly, since, in the present embodiment, a plurality of electrodemodules are laminated, it is possible to increase the capacity of theapparatus while yet making it compact.

Moreover, although a total of eight (8) electrode modules are laminatedin the present embodiment, the number of modules is not limited to eight(8) and similar effects may be obtained by laminating another number.

According to one aspect of the present invention there is provided anozonizer comprising:

-   -   a flat plate-shaped low voltage electrode;    -   a flat plate-shaped high voltage electrode facing a main surface        of the low voltage electrode;    -   a flat plate-shaped dielectric and a spacer for forming a        discharge gap of a thin thickness in a laminating direction        provided between the low voltage electrode and the high voltage        electrode;    -   an electrode cooling sheet provided facing a main surface of the        high voltage electrode at a side opposite the discharge gap for        cooling the high voltage electrode;    -   a thermal conducting/electric insulating sheet sandwiched        between the high voltage electrode and the electrode cooling        sheet; and    -   an alternating voltage is applied between the low voltage        electrode and the high voltage electrode and a discharge is        produced in the discharge gap injected with oxygen gas to        produce ozone gas. Thus, the cooling efficiency of the discharge        gaps is improved and the temperature of the discharge gaps may        be satisfactorily reduced. Accordingly, power density may be        increased without decreasing ozone generating efficiency, and        size reduction and cost reduction may be provided for an        apparatus in which it is possible to reduce the number of        electrode modules. Further, since the high voltage electrodes        are cooled via the thermal conducting/electric insulating        sheets, standard service water may be used as cooling water        without using ion exchanged water and the like of small electric        conductivity. Thus, an electric conductivity monitoring device        or ion exchanged water circulating equipment and the like is        unnecessary and, by reducing the number of apparatus components,        it is possible provide for cost reductions or reduce maintenance        costs.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   an ozone gas passage and a cooling water passage are formed        inside the low voltage electrode by adhering together two or        more metal flat plates formed with grooves on main surfaces        thereof so that the grooves line up. Hence, it is possible to        decrease the thickness of the low voltage electrode and reduce        the size of the apparatus. Furthermore, since piping for        deriving cooling water and ozone is unnecessary, assembly and        disassembly may be simply performed and a low cost ozonizer may        be provided.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   a cooling water passage is formed in the electrode cooling sheet        by adhering together two or more metal flat plates formed with        grooves on main surfaces thereof so that the grooves line up.        Thus, it is possible to decrease the thickness of the electrode        cooling sheet and reduce the size of the apparatus. Furthermore,        since piping for deriving cooling water and ozone is        unnecessary, assembly and disassembly may be simply performed        and a low cost ozonizer may be provided.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the flat metal plates are adhered together by heat and pressure        only.        Thus, ozone caused corrosion of the bonding agent does not occur        and it is possible to realize an ozonizer having a long life and        high reliability.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   both main surfaces of the low voltage electrode facing the        discharge gap are covered in an inorganic dielectric film.        Hence, the discharge gap constructed so as to be completely        sandwiched with the inorganic material, and metallic        contamination caused by metal sputtering in a discharge may be        suppressed and it is possible to provide an ozonizer which        generates clean ozone gas.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the dielectric film is made of a ceramic material. Hence the        ceramic dielectric film may be formed by a thermal spraying        technique and thickness thereof controlled to several μm.        Further, in accordance with this thermal spraying technique, it        is also possible to form the ceramic dielectric discharge gap        spacers concurrently.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the dielectric film is made of a glass material. Thus, the        dielectric film may be easily formed by adhering a glass plate        of a quartz material to the low voltage electrode by means of an        adhesive. Also, the convex glass dielectric discharge gap        spacers may be easily formed by means of a shot blasting        treatment using a mask prior to adhering the glass plate to the        low voltage electrode.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   a main surface of the dielectric facing the high voltage        electrode is coated with a conductive film having conductive        properties, and the conductive film contacts the high voltage        electrode. Hence, by applying the conductive film on the surface        of the dielectric and contacting this conductive film covered        surface and the high voltage electrode, even if, a gap occurs        between the conductive film and the high voltage electrode, the        conductive film and high voltage electrode have the same        electric potential and a local discharge may be prevented, and        it is possible to prevent the occurrence of metallic        contamination. Furthermore, since the high voltage electrode and        conductive film may be joined by simple pressure welding,        assembly and disassembly may be facilitated and there is also an        advantageous effect in that components may be recycled.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the dielectric and the high voltage electrode are adhered by        means of a conductive adhesive. Thus, gaps between the        dielectric and high voltage electrode may be eliminated a local        discharge may be prevented and it is possible to prevent the        occurrence of metallic contamination.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   a peripheral edge portion of the conductive film is coated with        an inorganic insulating film. Hence, it is possible to suppress        the abnormal corona discharge from occurring at the peripheral        edge portion of the conductive film and the occurrence of        metallic contamination may be prevented.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   a peripheral edge portion of the conductive adhesive is coated        with an inorganic insulating film. Thus, it is possible to        suppress the abnormal corona discharge from occurring at the        peripheral edge portion of the conductive adhesive and the        occurrence of metallic contamination may be prevented.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   an outside diameter of the high voltage electrode is smaller        than that of the dielectric. Thus, it is possible to eliminate        the abnormal corona discharge and prevent the occurrence of        metallic contamination. Also, it is possible to suppress damage        to the dielectric and an ozonizer having high reliability and a        long-life dielectric may be provided.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   an outside diameter of the high voltage electrode is smaller        than that of the conductive film covering the dielectric. Thus,        it is possible to further eliminate the abnormal corona        discharge and prevent the occurrence of metallic contamination.        Also, it is possible to further suppress damage to the        dielectric and an ozonizer having high reliability and a        long-life dielectric may be provided.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   a flexible thermal conducting sheet is sandwiched between the        high voltage electrode and the thermal conducting/electric        insulating sheet and the thermal conducting/electric insulating        sheet and the electrode cooling sheet, contacting each        respectively. Hence, minute gaps between the high voltage        electrode and the thermal conducting/electric insulating sheet        and the electrode cooling sheet and the thermal        conducting/electric insulating sheet are eliminated, it is        possible to eliminate minute gaps which degrade thermal        conductivity, the thermal conductivity between the high voltage        electrode and cooling sheet is improved, the cooling efficiency        of the discharge gaps is improved, the temperature of the        discharge gaps may be favorably lowered and the ozone generating        efficiency is improved. Furthermore, because the thermal        conductive sheets have elasticity, there is also an excellent        gas shielding effect by pressing from both sides with a        predetermined pressure.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the thermal conducting sheet is made of silicon and a ceramic        powder is applied to both main surfaces thereof. Thus, the        tackiness of the thermal conducting sheet is suppressed, air        bubbles may be easily eliminated between the high voltage        electrode and thermal conducting/electric insulating sheet and        electrode cooling sheet, mounting of the thermal conducting        sheet is facilitated and it is possible to provide a low-cost        ozonizer.

According to still another aspect of the present invention there isprovided an ozonizer comprising:

-   -   a flat plate-shaped low voltage electrode;    -   a flat plate-shaped high voltage electrode is provided facing a        main surface of the low voltage electrode;    -   a flat plate-shaped dielectric and a spacer for forming a        discharge gap of a thin thickness in a laminating direction        provided between the low voltage electrode and the high voltage        electrode;    -   an electrode cooling sheet provided facing a main surface of the        high voltage electrode at a side opposite the discharge gap for        cooling the high voltage electrode;    -   a flexible thermal conducting/electric insulating sheet        sandwiched between the high voltage electrode and the electrode        cooling sheet; and    -   an alternating voltage is applied between the low voltage        electrode and the high voltage electrode and a discharge is        produced in the discharge gap injected with oxygen gas to        produce ozone gas. Thus, the cooling efficiency of the discharge        gaps is improved and the temperature of the discharge gaps may        be satisfactorily reduced. Thus, power density may be increased        without decreasing ozone generating efficiency, and size        reduction and cost reduction may be provided for an apparatus in        which it is possible to reduce the number of electrode modules.        Further, since the high voltage electrodes are cooled via the        thermal conducting/electric insulating sheets, standard service        water may be used as cooling water without using ion exchanged        water and the like of a small electric conductivity. Thus, an        electric conductivity monitoring device or ion exchanged water        circulating equipment and the like is unnecessary and, by        reducing the number of apparatus components, it is possible        provide for cost reductions or reduce maintenance costs.

According to another aspect of the present invention there is providedan ozonizer comprising,

-   -   a manifold block provided between the low voltage electrode and        the electrode cooling sheet, and formed with a cooling water        passage connected with cooling water passages provided in the        low voltage electrode and the electrode cooling sheet,        respectively, or formed with an ozone gas passage connected with        the ozone gas passage provided in the low voltage electrode.        Hence, the space provided for piping for cooling water and for        piping for deriving ozone gas may be reduced, and it is possible        decrease the size of the apparatus, reduce the weight and reduce        the number of components and it is possible to provide for        increased quality of the apparatus.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the manifold block has an elastic structure with an elastic        function in a laminating direction of the low voltage electrode        and the high voltage electrode. Thus, it is possible to        eliminate the adverse influence on the gap length of the        discharge gap due to fastening the manifold block and the        precision of the discharge gaps may be improved.

According to another aspect of the present invention there is providedan ozonizer wherein,

-   -   the spacer is disposed at a position facing a rib forming the        cooling water passage of the low voltage electrode. Hence,        deformation of the low voltage electrode may be eliminated and,        consequently, deformation of the discharge gaps may be        suppressed and it is possible to form highly precise discharge        gaps.

According to still yet another aspect of the present invention there isprovided an ozonizer comprising:

-   -   a flat plate-shaped low voltage electrode;    -   a flat plate-shaped high voltage electrode provided facing both        main surfaces of the low voltage electrode;    -   a flat plate-shaped dielectric and a spacer for forming a        discharge gap of a thin thickness in a laminating direction        provided between the low voltage electrode and the high voltage        electrode;    -   an electrode cooling sheet provided facing a main surface of the        high voltage electrode at a side opposite the discharge gap for        cooling the high voltage electrode;    -   a thermal conducting/electric insulating sheet sandwiched        between the high voltage electrode and the electrode cooling        sheet;    -   a manifold block provided between the low voltage electrode and        the electrode cooling sheet, and formed with a cooling water        passage connected with cooling water passages provided in the        low voltage electrode and the electrode cooling sheet, or formed        with an ozone gas passage connected with the ozone gas passage        provided in the low voltage electrode;    -   both main surfaces of the low voltage electrode facing the        discharge gap are covered in an inorganic dielectric film;    -   a main surface of the dielectric facing the high voltage        electrode coated with a conductive film having conductive        properties, and the conductive film contacts the high voltage        electrode;    -   a flexible thermal conducting sheet is sandwiched between the        high voltage electrode and the thermal conducting/electric        insulating sheet and the thermal conducting/electric insulating        sheet and the electrode cooling sheet, contacting each        respectively; and    -   an alternating voltage is applied between the low voltage        electrode and the high voltage electrode and a discharge is        produced in the discharge gap injected with oxygen gas to        produce ozone gas. Thus, it is possible to form discharge gaps        for generating clean ozone in which metallic contamination does        not develop and the cooling efficiency of the discharge gaps 6        may be improved.

According to still yet another aspect of the present invention there isprovided an ozonizer wherein,

-   -   a plurality of electrode modules comprising the low voltage        electrode, the high voltage electrode, the dielectric, the        spacer, the electrode cooling sheet and the first and second        thermal conducting/electric insulating sheet are laminated.        Thus, it is possible to change the capacity of the apparatus in        accordance with the number of electrode modules which are        laminated and the capacity may be easily increased; on the other        hand, the apparatus may be made compact even if the capacity is        increased.

1. An ozonizer comprising: at least one electrode module, electrodemodules being stackable upon each other, each electrode modulecomprising laminated; : a flat plate-shaped low voltage electrodeincluding a cooling water passage and an ozone passage inside said lowvoltage electrode; a flat plate-shaped high voltage electrode facingsaid low voltage electrode; a flat plate-shaped dielectric disposed onsaid high voltage electrode and facing said low voltage electrode; aspacer located between said dielectric on said low voltage electrode andsaid high voltage electrode, and defining a discharge gap between saiddielectric on said low voltage electrode and said high voltageelectrode; and a thermally conducting and electrically insulating sheetdisposed on said high voltage electrode; a manifold block disposed onsaid low voltage electrode and having passages for circulating waterthrough said cooling water passage and a passage for extracting ozonefrom said discharge gap through said ozone passage; and an electrodecooling sheet disposed on said thermally conducting and electricallyinsulating sheet and on said manifold block, at an outermost side ofsaid electrode module, for cooling said high voltage electrode.
 2. Theozonizer according to claim 1, wherein said low voltage electrodecomprises at least two flat metal plates including grooves and adheredtogether with the grooves aligned to form said ozone passage and saidcooling water passage inside said low voltage electrode.
 3. The ozonizeraccording to claim 2, wherein said spacer is disposed at a positionfacing a rib forming said cooling water passage of said low voltageelectrode.
 4. The ozonizer according to claim 1 wherein said electrodecooling sheet comprises at least two flat metal plates including groovesand adhered together with the grooves aligned to form said cooling waterpassage inside said electrode cooling sheet.
 5. The ozonizer accordingto claim 1 including an inorganic dielectric film covering a mainsurface of said low voltage electrode facing said discharge gap.
 6. Theozonizer according to claim 1 including an electrically conductive filmcoating a main surface of said dielectric facing said high voltageelectrode, wherein said conductive film contacts said high voltageelectrode.
 7. The ozonizer according to claim 6 including an inorganicinsulating film coating a peripheral edge portion of said conductivefilm.
 8. The ozonizer according to claim 1 including a conductiveadhesive adhering said dielectric and said high voltage electrodetogether.
 9. The ozonizer according to claim 8 including an inorganicinsulating film coating a peripheral edge portion of said conductivefilm adhesive.
 10. The ozonizer according to claim 9 6, wherein saidhigh voltage electrode has a diameter smaller than an outside diameterof said conductive film covering said dielectric.
 11. The ozonizeraccording to claim 1, wherein said high voltage electrode has an outsidediameter smaller than an outside diameter of said dielectric.
 12. Theozonizer according to claim 1 including a flexible thermally conductingsheet sandwiched between said high voltage electrode and said thermallyconducting and electrically insulating sheets sheet, and said thermallyconducting and electrically insulating sheet and said low voltageelectrode or said electrode cooling sheet, contacting each of said highvoltage electrode, said thermally conducting and electrically insulatingsheet, and said electrode cooling sheet, respectively.
 13. The ozonizeraccording to claim 12, wherein said flexible thermally conducting sheetis a silicone coated with a ceramic powder on major surfaces of saidflexible thermally conducting sheet.
 14. The ozonizer according to claim1, wherein said manifold block has an elastic structure with an elasticfunction in the laminating direction of said low voltage electrode andsaid high voltage electrode.
 15. The ozonizer according to claim 14,wherein said manifold block comprises two block pieces stacked in alaminating direction of said electrode module and including said passagefor cooling water and said passage for ozone, an expandable jointextending between said two block pieces, and an elastic member disposedbetween said two block pieces.
 16. The ozonizer according to claim 1,including a generator cover filled with oxygen and containing saidelectrode module, said electrode cooling sheet, and said manifold block,wherein the oxygen is introduced into said discharge gap at acircumferential portion of said discharge gap and the ozone in saiddischarge gap is extracted from a central portion of said discharge gap.17. The ozonizer according to claim 1, comprising a first clampmechanism for clamping said electrode module together, aid and a secondclamp mechanism, independent of said first clamp mechanism, for clampingsaid manifold block together.
 18. The ozonizer according to claim 17,wherein said flat metal plates are adhered together by heat and pressureonly.
 19. An ozonizer comprising: at least one electrode moduleelectrode modules being stackable upon each other, each electrode modulecomprising laminated; : a flat plate-shaped low voltage electrodeincluding a cooing cooling water passage and an ozone passage insidesaid low voltage electrode; a flat plate-shaped high voltage electrodefacing said low voltage electrode; a spacer disposed between said lowvoltage electrode and said high voltage electrode, defining a dischargegap between said low voltage electrode and said high voltage electrode;and a thermally conducting and electrically insulating sheet disposed onsaid high voltage electrode; a manifold block located on said lowvoltage electrode and including a passage for circulating water throughsaid cooling water passage in said low voltage electrode and including apassage for extracting ozone from said discharge tap gap through saidozone passage; an electrode cooling sheet disposed on said insulatingsheet and on said manifold block, at an outermost side of said electrodemodule for cooling said high voltage electrode. ; an inorganicdielectric film covering main surfaces of said low voltage electrodefacing said discharge gap; an electrically conductive film coating amain surface of said inorganic dielectric film facing said high voltageelectrode, wherein said conductive film contacts said high voltageelectrode; and a flexible thermally conducting sheet sandwiched betweensaid high voltage electrode and said thermally conducting andelectrically insulating sheet, and said thermally conducting andelectrically insulating sheet and said low voltage electrode or saidelectrode cooling sheet, contacting each of said high voltage electrode,said thermally conducting and electrically insulating sheet, and saidelectrode cooling sheet, respectively.